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Vulnerability record · CVE-2026-25536 · published 4 February 2026

CVE-2026-25536: Lfprojects mcp typescript sdk race condition vulnerability

Lfprojects · Mcp Typescript Sdk

MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. From version 1.10.0 to 1.25.3, cross-client response data leak when a single McpServer/Server and transport instance is reused across multiple client connections, most commonly in stateless StreamableHTTPServerTransport deployments. This issue has been patched in version 1.26.0.

7.1 CVSS 3.1 High EPSS 0.36% · top 73.0% CWE-362 · Race conditionCWE-367 · TOCTOU race condition
7.1CVSS 3.1 base score
0.36%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
7References
15 Jul 2026Last modified by NVD

Description

MCP TypeScript SDK is the official TypeScript SDK for Model Context Protocol servers and clients. From version 1.10.0 to 1.25.3, cross-client response data leak when a single McpServer/Server and transport instance is reused across multiple client connections, most commonly in stateless StreamableHTTPServerTransport deployments. This issue has been patched in version 1.26.0.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/modelcontextprotocol/typescript-sdk/issues/204 Issue TrackingVendor Advisory
https://github.com/modelcontextprotocol/typescript-sdk/issues/243 Issue TrackingVendor Advisory
https://github.com/modelcontextprotocol/typescript-sdk/security/advisories/GHSA-345p-7cg4-v4c7 MitigationVendor Advisory
https://access.redhat.com/errata/RHSA-2026:3960
https://access.redhat.com/security/cve/CVE-2026-25536
https://bugzilla.redhat.com/show_bug.cgi?id=2436937
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-25536.json

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-25536), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.